The present invention relates to the art of providing protection for active food ingredients, and, in particular, to protecting food ingredients by encapsulation.
It has been known in the art of food preparation to provide protection for different ingredients included in food compositions by means of protective coatings. Such protective systems have been employed for various reasons such as for protection of the active ingredient, both while on the shelf and during use, and for prolonged release in the oral cavity and/or systemically. As used herein, "active ingredient" can be an ingredient such as a sweetener, soluble dietary fiber, a flavoring agent, a bio-effecting ingredient, such as a medicinal drug or pharmaceutical agent, and a breath-freshening ingredient.
Protective systems for active ingredients encounter unique problems when used in chewing gum compositions since gum compositions include a soluble portion which is consumed during chewing and an insoluble masticatory portion which remains in the oral cavity as a cud or bolus throughout chewing. The soluble portion is added by blending soluble bulking agents, flavorants, natural and synthetic sweeteners, etc. to the gum base usually in the presence of heat in order to effectuate mixing. Thus, a protective system for an active must be able to withstand the rigors of heat and shear forces. Furthermore, since the gum base includes basically insoluble ingredients such as resins, elastomers, etc., any protection for an active ingredient included in the base would have to be compatible to a certain degree with such components. Depending on the effect desired, the protected active ingredient can be incorporated into the base and/or added with the soluble components or added after compositing.
Dipeptide sweeteners such as L-aspartyl-L-phenyl-alanine methylester (aspartame), which have been widely recognized as an extremely good-tasting non-caloric sweetener for use in a variety of food products, have been found to be particularly troublesome, especially, when used in chewing gum products. Unfortunately, aspartame is extremely unstable in the presence of moisture and undergoes hydrolytic degradation and subsequent loss of sweetness. Elevated temperatures and specific pH ranges may accelerate the hydrolytic degradation. Additionally, aspartame is known to react with a number of flavorings and chemicals such as aldehydes and ketones. For example, aspartame loses its sweetness due to chemical reactions in the presence of flavor aldehyde-containing oils such as cinnamon. These flavor oils are used in food products and are popular in chewing gum and other confectionery products. These compositions also generally contain moisture and may be exposed to elevated temperatures during their shelf life. The result is the loss of aspartame and the corresponding loss of sweetness contributed thereby in the gum.
For example, U.S. Pat. No. 3,962,463 to Witzel discloses chewing gum containing on its surface tiny capsules of flavoring and/or flavors fixed on an edible substrate which will release the flavor upon mastication. The flavoring ingredient can be micro-encapsulated in gelatin, waxes, polyethylene and the like, and printed on the surface of the gum as an aqueous slurry. The encapsulation can be effected in a conventional manner by blending liquid flavoring with a concentrated aqueous solution of gelatin at a temperature below 25.degree. C. whereby a fine stable emulsion is formed. After treatment to impart moisture resistance, the emulsion can be spray dried while still cool to produce a fine free-flowing powder each particle of which consists of a core of flavoring surrounded by a dry gelatin wall. The gelatin micro-encapsulated flavoring ingredient can be printed on the gum by either direct or off-set Gravure printing. As can be seen, the provision of a protection system according to the above-disclosure is a rather complex procedure which requires an additional manufacturing step in order to be added to the gum product.
Other disclosures show the use of protective encapsulation of artificial sweeteners such as aspartame, saccharin, etc. For example, U.S. Pat. Nos. 4,122,195 and 4,139,639 disclose encapsulation of aspartame in Capsul dextrin and gum arabic. However, such encapsulants have been found to be of only limited effectiveness in preventing degradation of moisture sensitive aspartame since these encapsulants are hydrophilic and moisture-permeable.
U.S. Pat. No. 4,384,004 to Cea, et al. discloses preparation of an artificial sweetener, i.e., APM, in an encapsulated form with at least one layer of a coating material selected from the group consisting of cellulose, cellulose derivatives, starches, carbohydrates, gums, polyolefins, polyesters, waxes, vinyl polymers, gelatin, zein, and mixtures thereof in a ratio of coating material to APM which does not exceed 1:1. This coating material is applied to the APM while it is in solid particle form at temperatures below the decomposition temperature of APM, e.g., up to about 200 .degree., and preferably about 100.degree. to 115.degree. F. The application of the Cea, et al. protective system requires a rather elaborate energy-intensive coating procedure, e.g., fluidized bed coating process, in which a strong upward stream or air current must be provided. This results from, among other things, the requirement of providing the protective coating material in a solvent.
EPA No. 81110320.0, published June 16, 1982 (Publication No. 0053844), to Ajinomoto Co., Inc., discloses a stabilized dipeptide-based sweetening composition comprising (a) from 20 to 60% by weight of solid fat, (b) from 10 to 30% by weight emulsifier, (c) from 10 to 30% by weight polysaccharide and (d) not more than 30% by weight of dipeptide sweetener. The compositions are prepared by heating the mixture of the ingredients, cooling, and pulverizing to obtain powder of granules of the composition to obtain a ASTM mesh size of smaller than 12. Spray drying the mixture is also disclosed.
U.S. Pat. No. 4,105,801 to Degliotti, discloses a confectionary comprising a core portion and a shell adheringly enveloping the core portion, whereby the shell is formed by an intimate mixture of microcrystals of xylitol with a solid fatty substance in a proportion of 0.5 to 15 parts by weight of fatty substance to each 100 parts by weight of xylitol. The fatty substance is preferably a mono-, di- or triglyceride having a melting range of between 20.degree. and 60.degree. C.
While it would seem that hydrophobic encapsulating agents provide better impermeability and gradual release characteristics than hydrophilic coatings, it is not known whether any hydrophobic coatings have been successfully employed in the past for chewing gum ingredients. Most hydrophobic materials which could be used as encapsulants, such as a low molecular weight polyvinyl acetate, waxes and fats, are dissolved in the chewing base when they are mixed into the heated gum mass during the gum manufacturing process.
Other hydrophobic materials such as high molecular weight polyvinyl acetate and styrene butadiene rubber are substantially insoluble in food grade solvents which are required in encapsulating processes. However, U.S. Pat. No. 3,826,847 to Ogawa, et al. discloses encapsulation of seasonings including sugar by use of high molecular weight polymers such as high molecular weight polyvinyl acetate; e.g., having a degree of polymerization of 400. Ogawa, et al. describe combining the seasoning by dissolving the polyvinyl ester in a solvent such as ethanol, ethyl acetate and the like to obtain a 2-30% by weight solution to which the seasoning is subsequently added with agitation in an amount at 1-20 times the polyvinyl ester content to form a homogenous dispersion. Then a liquid which is miscible with the solution but immiscible with the polyvinyl ester, such as ether, hexane, or the like, is slowly added to the dispersion so that polyvinyl ester granules integrated with the seasoning are separated out in the form of non-adhesive particles for incorporation into chewing gum base. The particle size can be less than 20 mesh, and preferably are less than 48 mesh. In order to produce the particulate, however, several decantations are required as well as a drying procedure, such as energy-intensive suction.
Yet another protective system for encapsulation has been disclosed in PCT/US No. 84,00108 including a shellac encapsulant, which is hydrophobic and insoluble in the gum base yet soluble in food-grade solvents, to provide a substantially impermeable coating for active ingredients, such as aspartame. The method of encapsulation can be effected by coating with a shellac-containing solution primarily by a fluidized bed coating method wherein particles of the active ingredient are suspended in a stream of pressurized air and sprayed with a solution of the encapsulating agent. The particles can also be coated in a roller bed coating method wherein a suspension of the active agent and its solvent is deposited on a heated, rotating drum, the solvent being evaporated by the heat leaving coated ingredient particles which are scraped from the roller. In each of these methods, and, generally, all methods of encapsulating which includes a solvent, an energy-intensive step to drive off the solvent is required before use in the end food product.
It is therefore, an object of the present invention to provide an active ingredient protection system which can be easily included in a food composition such as a chewing gum composition without an additional step in the manufacturing process.
Another object of the present invention is to provide an encapsulation system which is highly effective in preventing deterioration from moisture.
A further object of the invention is to provide an encapsulation system which can be applied without the use of a solvent system.
Still another object of the present invention is to provide an encapsulated active ingredient with a highly-controlled release characteristic for use in a food product.
Yet another object of the present invention is to provide a protective system for artificial sweeteners which deteriorate in the present of moisture for use in a chewing gum composition.
Another object of the invention is to provide a chewing gum composition with a highly-controlled active ingredient protection and release system.
Other and further objects will become apparent to those skilled in the art in view of the disclosure set forth herein.